terms for other categories of relative whom we include under the designations brother- and sister- in-law. Similar conditions are general throughout Melanesia. If, as Professor Kroeber has supposed, the classing of the brother-in-law with the brother be due to the psychological similarity of the relationships, we ought to be able to discover why this similarity should be greater between persons of different sex than between persons of the same sex.
If now we study our case from the Banks Islands more closely and compare the social conditions in Merlav with those of other islands of the group, we find definite evidence, which it will not now be possible to consider in detail, showing that sexual relations were formerly allowed between a man and his wife's sisters and his brothers' wives, and that there is a definite association between the classing of these relatives with the sister and the cessation of such sexual relations. If such people as the Melanesians wish to emphasise in the strongest manner possible the impropriety of sexual relations between a man and the sisters of his wife, there is no way in which they can do it more effectually than by classing these relatives with a sister. To a Melanesian, as to other people of rude culture, the use of a term otherwise applied to a sister carries with it such deeply-seated associations as to put sexual relations absolutely out of the question. There is a large body of evidence from southern Melanesia which suggests strongly,
